From the OP's link:
Get connected with this high-speed HDMI cable that features HD polyethylene composition to ensure critical signal-pair geometry and a Dielectric-Bias System that reduces distortion. The 100% Perfect-Surface Silver conductors improve signal clarity.
Entirely legal, none of the claims written sound false.
(Using entirely madeup numbers) A regular might deliver 95% "clarity", while this one might do 99%. HDMI as a digital standard can handle transmission errors and re-send still resulting in 100% of the data being received, so you dont actually need the improved signal quality. So what they state in that blurb is presumedly completely true - just completely unimportant.
Its just like digital free-to-air TV - once you cross a certain threshold of signal strength you get a pixel-perfect picture - ie, an exact replication of what the television network has broadcast. At that point, you could install a whiz-bang antenna but there's no point, as you are already getting 100% of the decoded data.